Conventionally, there has been high demand for an improvement in soil resistance of a fiber structure of a fabric such as a woven or knitted fabric, and various methods for improving the soil resistance have been proposed. In general, as a method for imparting soil resistance to a fiber structure, the following methods have been studied: a processing method of imparting a hydrophilic resin to a fiber structure for improving the affinity of the fiber structure to a washing liquid so as to facilitate release of a soil, and a processing technique of imparting a water- and oil-repellent resin to a fiber structure for suppressing adhesion of a soil to the fibers.
The method of imparting a hydrophilic resin to a fiber structure, however, has a problem that if an aqueous soil adheres to the fiber structure, the soil is likely to expand largely. In addition, the technique of imparting a water- and oil-repellent resin to a fiber structure has a problem that it is difficult to wash away a once adhered soil, and soil redeposition or the like is likely to occur, since the affinity of the fiber structure to a washing liquid is lowered due to the water repellency.
In view of these problems, it has been studied to impart a water- and oil-repellent resin containing a hydrophilic group to fibers in order to satisfy both the soil resistance and soil releasability.